Switching power supply circuit

Abstract

The utility model discloses a switching power supply circuit, belongs to the field of medical power supplies, and solves the problems of complex structure and unstable output voltage in the prior art. The power supply mainly comprises a rectification and voltage regulation module, the rectification and voltage regulation module is connected with an inverter circuit, and the inverter circuit is electrically connected with a rectification filter circuit. The rectification filter circuit is connected with the step-down circuit, a feedback circuit is electrically connected between the rectification filter circuit and the step-down circuit, and the feedback circuit is connected with the inverter circuit. According to the utility model, an independent filtering device with poor reliability is cancelled, and the anti-interference capability of the switching power supply is improved by adopting the rectification inverter circuit and cooperating with the decoupling capacitor.

Description

Technical Field

[0001] The utility model relates to the field of medical power supplies, and in particular to a switching power supply circuit. Background Art

[0002] At present, the electromagnetic compatibility requirements in the field of medical devices are strict, and it is necessary to change the mains voltage from 220V 50Hz to the direct current required by medical devices. In the prior art, the application with publication number CN206180878U discloses a switching power supply circuit, which includes a bridge rectifier and a power factor correction circuit. The power factor correction circuit includes a switching circuit, a first boost diode, a second boost diode, an inductor and a capacitor, but it does not have a feedback circuit and the output voltage is unstable. In addition, most medical devices on the market are finished switching power supplies that are combined with independent filtering devices to form a switching power supply circuit to meet the electromagnetic compatibility requirements. This method has poor reliability, weak load capacity, and damage will cause the electromagnetic compatibility protection capability to fail or even damage the internal components of the product. Utility Model Content

[0003] The purpose of the utility model is to provide a switching power supply circuit to solve the problems of complex structure and unstable output voltage in the prior art.

[0004] The utility model is realized by the following technical solutions:

[0005] A switching power supply circuit comprises a rectifier and voltage regulation module, an inverter circuit, a rectifier and filter circuit and a step-down circuit. The rectifier and voltage regulation module, the inverter circuit, the rectifier and filter circuit and the step-down circuit are electrically connected in sequence. A feedback circuit is electrically connected between the rectifier and filter circuit and the step-down circuit. The feedback circuit is connected to the inverter circuit. The feedback circuit comprises a controllable diode IC5. The anode of the controllable diode IC5 is connected to the step-down circuit. The cathode of the controllable diode IC5 is connected to an optocoupler IC2. The optocoupler IC2 is electrically connected to a voltage stabilizing chip IC1. The voltage stabilizing chip IC1 is connected to a field effect transistor Q1. The field effect transistor Q1 adopts a depletion-type MOSFET. Its gate is connected to the voltage stabilizing chip IC1, its source is connected to the rectifier and voltage regulation module, and its drain is connected to the inverter circuit. The inverter circuit comprises a transformer T1 and a transformer T2.

[0006] Furthermore, the rectifier and voltage regulator module adopts a bridge rectifier circuit, which includes a diode D1, a diode D2, a diode D3 and a diode D4, and the bridge rectifier circuit is electrically connected to the transformer T1 and the transformer T2 respectively.

[0007] Furthermore, the inverter circuit includes capacitor C1, capacitor C2, diode D5 and diode D6. The output end of the transformer T1 is connected in parallel with capacitor C1, and a diode D5 is connected in series between the transformer T1 and capacitor C1. The output end of the transformer T2 is connected in parallel with capacitor C2, and a diode D6 is connected in series between the transformer T1 and capacitor C2. Both diode D5 and diode D6 are connected to terminal CH1.

[0008] Furthermore, a buck chip IC3 and a buck chip IC4 are provided between the diode D5 and the terminal CH1.

[0009] Furthermore, the optical coupler IC2 adopts a PC817 chip.

[0010] Compared with the prior art, the beneficial effects of the utility model are:

[0011] The utility model eliminates the independent filtering device with poor reliability, adopts the rectifier inverter circuit and cooperates with the decoupling capacitor to improve the anti-interference ability of the switching power supply. When the power supply is affected by external interference and the voltage is too high, the controllable diode IC5 and the optical coupler IC2 cooperate to maintain the voltage output stably. The utility model is equipped with two transformers, which cooperate with the step-down chip IC3 and the step-down chip IC4 to output a variety of required voltages. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a circuit schematic diagram of the utility model;

[0013] Figure 2 It is a flow chart of the utility model. DETAILED DESCRIPTION

[0014] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is clearly and completely described below in conjunction with the drawings of the present invention. Based on the embodiments in this application, other similar embodiments obtained by ordinary technicians in this field without making creative work should all fall within the scope of protection of this application. In addition, the directional words mentioned in the following embodiments, such as "up", "down", "left", "right", etc., are only referenced to the directions of the drawings. Therefore, the directional words used are used to illustrate rather than limit the creation of the present invention.

[0015] The utility model is further described below in conjunction with the accompanying drawings.

[0016] Embodiment 1: A switching power supply circuit, such as Figure 1 and Figure 2As shown, it includes a rectifier and voltage regulation module, an inverter circuit, a rectifier and filter circuit and a step-down circuit. The inverter circuit, the rectifier and filter circuit and the step-down circuit are electrically connected in sequence. A feedback circuit is electrically connected between the rectifier and filter circuit and the step-down circuit, and the feedback circuit is connected to the inverter circuit. The feedback circuit includes a controllable diode IC5, the anode of the controllable diode IC5 is connected to the step-down circuit, the controllable diode IC5 adopts a TL431 voltage regulator, the cathode of the controllable diode IC5 is connected to an optocoupler IC2, the optocoupler IC2 adopts a PC817 chip, the optocoupler IC2 is electrically connected to a voltage regulator chip IC1, the voltage regulator chip IC1 adopts an OB2269 chip, the voltage regulator chip IC1 is connected to a field effect transistor Q1, the field effect transistor Q1 adopts a 5N60 depletion MOSFEI, its gate is connected to the voltage regulator chip IC1, its source is connected to the rectifier and voltage regulation module, and its drain is connected to the inverter circuit; the inverter circuit includes a transformer T1 and a transformer T2. The utility model converts the 311V DC voltage completed by the first-level voltage regulation into the DC power required by the weak current circuit.

[0017] Embodiment 2: A switching power supply circuit, such as Figure 1 As shown, the rectifier and voltage regulator module adopts a bridge rectifier circuit, which includes a diode D1, a diode D2, a diode D3 and a diode D4, and the bridge rectifier circuit is electrically connected to the transformer T1 and the transformer T2 respectively; the inverter circuit includes a capacitor C1, a capacitor C2, a diode D5 and a diode D6, the output end of the transformer T1 is connected in parallel with the capacitor C1, and the diode D5 is connected in series between the transformer T1 and the capacitor C1; the output end of the transformer T2 is connected in parallel with the capacitor C2, and the diode D6 is connected in series between the transformer T1 and the capacitor C2; The diode D5 and the diode D6 are both connected to the terminal CH1; a buck chip IC3 and a buck chip IC4 are arranged between the diode D5 and the terminal CH1, the buck chip IC3 and the buck chip IC4 both use XL4015 chips, the cathode of the diode D5 is respectively connected to the ports of the buck chip IC3 and the buck chip IC4, the buck chip IC3 and the buck chip IC4 are connected to the terminal CH1, the anode of the controllable diode IC5 is connected to the buck chip IC3, and the reference end of the controllable diode IC5 is electrically connected between the inverter circuit and the buck circuit. The rest is the same as that of the first embodiment.

[0018] like Figure 1As shown, the 311V voltage after the first-stage voltage regulation is converted into 24V AC through transformer T1, and then rectified and filtered by diode D5 and capacitor C1 to 24V DC, and transmitted to pin 1 of terminal CH1; it is also transmitted to pin 5 of buck chip IC3 and pin 5 of buck chip IC4 to reduce the 24V DC to 5V and 12V. After pin 3 of voltage regulator chip IC1 is energized, field effect tube Q1 is turned on, and converted into -12V AC through transformer T2, and then rectified and filtered by diode D6 and capacitor C2 to -12V DC to pin 5 of terminal CH1.

[0019] When the power supply is affected by external interference and the voltage is too high, the controllable diode IC5 is turned on to energize the optocoupler IC2, so that the 2nd pin of the voltage regulator chip IC1 is energized, and the 8th pin of the voltage regulator chip IC1 is turned off after energization. On the contrary, if the voltage is too low, the 8th pin of the voltage regulator chip IC1 will continue to output, thereby maintaining a stable voltage output. The switching power supply of the utility model has high anti-interference and integrated filtering function, can meet the electromagnetic compatibility requirements without an independent filtering device, and has the characteristics of low cost and high output power.

[0020] The present invention has been described in detail above. The above description is only a preferred embodiment of the present invention and should not limit the scope of implementation of the present invention. That is, all equivalent changes and modifications made within the scope of this application should still fall within the scope of the present invention.

Claims

1. A switching power supply circuit, comprising a rectifier and voltage regulator module, characterized in that: It also includes an inverter circuit, a rectifier and filter circuit and a step-down circuit. The rectifier and voltage regulation module, the inverter circuit, the rectifier and filter circuit and the step-down circuit are electrically connected in sequence. A feedback circuit is electrically connected between the rectifier and filter circuit and the step-down circuit. The feedback circuit is connected to the inverter circuit. The feedback circuit includes a controllable diode IC5. The controllable diode IC5 is connected to an optocoupler IC2. The optocoupler IC2 is electrically connected to a voltage regulator chip IC1. The voltage regulator chip IC1 is connected to a field effect transistor Q1. The inverter circuit includes a transformer T1 and a transformer T2.

2. The switching power supply circuit according to claim 1, characterized in that: The rectifier and voltage regulator module adopts a bridge rectifier circuit, which includes a diode D1, a diode D2, a diode D3 and a diode D4. The bridge rectifier circuit is electrically connected to the transformer T1 and the transformer T2 respectively.

3. The switching power supply circuit according to claim 2, characterized in that: The inverter circuit includes capacitor C1, capacitor C2, diode D5 and diode D6. The output end of transformer T1 is connected in parallel with capacitor C1, and diode D5 is connected in series between transformer T1 and capacitor C1. The output end of transformer T2 is connected in parallel with capacitor C2, and diode D6 is connected in series between transformer T1 and capacitor C2. Diode D5 and diode D6 are both connected to terminal CH1.

4. The switching power supply circuit according to claim 3, characterized in that: A buck chip IC3 and a buck chip IC4 are provided between the diode D5 and the terminal CH1.

5. The switching power supply circuit according to claim 4, characterized in that: The optical coupler IC2 adopts PC817 chip.

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